Patents by Inventor Katsuhiko Koui

Katsuhiko Koui has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20120134048
    Abstract: According to one embodiment, a spin torque oscillator includes a field generation layer, a spin injection layer including a first layer and a second layer, and an interlayer interposed between the field generation layer and the spin injection layer, wherein the first layer is interposed between the second layer and the interlayer and includes a (001)-oriented Heuslar magnetic alloy or a (001)-oriented magnetic material having a body-centered cubic lattice structure.
    Type: Application
    Filed: August 25, 2011
    Publication date: May 31, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akihiko TAKEO, Norihito FUJITA, Mariko KITAZAKI, Katsuhiko KOUI, Hitoshi IWASAKI
  • Patent number: 8169741
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main pole which generates a recording magnetic field, a return pole which forms a closed magnetic circuit for the recording magnetic field, and a side shield magnetically spaced from the main pole in a cross-track direction in which a point on a trailing edge of the side shield which is closest to the main pole is positioned on a leading side of a trailing edge of the main pole.
    Type: Grant
    Filed: May 3, 2007
    Date of Patent: May 1, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoko Taguchi, Tomomi Funayama, Yuka Aoyagi, Katsuhiko Koui
  • Patent number: 8153188
    Abstract: The present invention relates to a method for manufacturing a magnetoresistive element having a magnetization pinned layer, a magnetization free layer, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer. A process of forming the spacer layer in the method includes depositing a first metal layer forming the metal paths, depositing a second metal layer on the first metal layer, performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas, and converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.
    Type: Grant
    Filed: October 9, 2008
    Date of Patent: April 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Katsuhiko Koui, Hiromi Yuasa, Susumu Hashimoto, Hitoshi Iwasaki
  • Publication number: 20120002325
    Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole generating a recording magnetic field in a magnetic recording medium, a return yoke paired with the main magnetic pole, and a spin torque oscillator interposed between the main magnetic pole and the return yoke and including a spin injection layer, an oscillation layer, a nonmagnetic metal layer, and spin assist layer stacked in this order, wherein the nonmagnetic metal layer includes at least one metal selected from the group consisting of Cu, Au, Ag, Al, Pd, Pt, Os, and Ir, and the spin assist layer is a soft magnetic layer whose saturation magnetic flux density (Bs), diamagnetic field coefficient (N) and gap magnetic field (Hg) show a relationship expressed by Bs×N>Hg.
    Type: Application
    Filed: June 28, 2011
    Publication date: January 5, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Soichi OIKAWA, Katsuhiko Koui
  • Publication number: 20120002331
    Abstract: According to one embodiment, there is provided a magnetic recording head including a main pole, and a spin torque oscillator provided adjacent to the main pole and includes an oscillation layer including a first magnetic layer and a second magnetic layer and a third magnetic layer provided closer to the second magnetic layer and configured to inject a spin into the oscillation layer. The first magnetic layer has a saturation flux density of 1 T or more and 1.9 T or less.
    Type: Application
    Filed: June 28, 2011
    Publication date: January 5, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Soichi OIKAWA, Kenichiro YAMADA, Katsuhiko KOUI, Masayuki TAKAGISHI
  • Patent number: 8085511
    Abstract: A magnetoresistance effect element includes a magnetoresistance effect film including a magnetically pinned layer having a magnetic material film whose direction of magnetization is pinned substantially in one direction, a magnetically free layer having a magnetic material film whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic metal intermediate layer located between said pinned layer and said free layer. The element also includes a pair of electrodes electrically connected to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film. At least one of the pinned layer and the free layer may include a thin-film insertion layer.
    Type: Grant
    Filed: September 23, 2008
    Date of Patent: December 27, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
  • Patent number: 8081397
    Abstract: A magnetic head assembly includes a magnetic recording head, a main magnetic pole, a head slider, a suspension and an actuator arm. The magnetic recording head includes a main magnetic pole having an air bearing surface facing a magnetic recording medium; and a stacked structure having, a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. A stacked plane of the stacked structure is inclined with respect to the air bearing surface. The magnetic recording head is mounted on the head slider. The head slider is mounted on one end of the suspension. The actuator arm is connected to the other end of the suspension.
    Type: Grant
    Filed: June 18, 2009
    Date of Patent: December 20, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Kenichiro Yamada, Katsuhiko Koui, Hitoshi Iwasaki, Masayuki Takagishi, Masahiro Takashita, Mariko Shimizu, Soichi Oikawa
  • Patent number: 8064244
    Abstract: A spin valve structure for a spintronic device is disclosed and includes a composite seed layer made of at least Ta and a metal layer having a fcc(111) or hcp(001) texture to enhance perpendicular magnetic anisotropy (PMA) in an overlying (Co/Ni)x multilayer. The (Co/Ni)x multilayer is deposited by a low power and high Ar pressure process to avoid damaging Co/Ni interfaces and thereby preserving PMA. As a result, only a thin seed layer is required. PMA is maintained even after annealing at 220° C. for 10 hours. Examples of GMR and TMR spin valves are described and may be incorporated in spin transfer oscillators and spin transfer MRAMs. The free layer is preferably made of a FeCo alloy including at least one of Al, Ge, Si, Ga, B, C, Se, Sn, or a Heusler alloy, or a half Heusler alloy to provide high spin polarization and a low magnetic damping coefficient.
    Type: Grant
    Filed: June 19, 2009
    Date of Patent: November 22, 2011
    Assignees: TDK Corporation, Kabushiki Kaisha Toshiba
    Inventors: Kunliang Zhang, Min Li, Yuchen Zhou, Soichi Oikawa, Kenichiro Yamada, Katsuhiko Koui
  • Publication number: 20110242701
    Abstract: According to one embodiment, a magnetic head includes a main pole configured to apply a perpendicular recording magnetic field to a recording layer of a recording medium, a return pole opposed to the trailing side of the main pole with a write gap therebetween and configured to reflux magnetic flux from the main pole to form a magnetic circuit in conjunction with the main pole, a coil configured to excite magnetic flux in the magnetic circuit includes the main pole and the return pole, a plurality of high-frequency oscillatory elements individually interposed between the main pole and the return pole, includes a plurality of magnetic films different in magnetic resonance frequency, and configured to individually apply high-frequency magnetic fields to the recording medium, and an electrical circuit configured to energize the high-frequency oscillatory elements.
    Type: Application
    Filed: January 28, 2011
    Publication date: October 6, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masaya Ohtake, Tomoko Taguchi, Masayuki Takagishi, Kenichiro Yamada, Katsuhiko Koui
  • Patent number: 8027118
    Abstract: According to one embodiment, an apparatus for controlling a head includes a transmitting module and a controller. The transmitting module is configured to transmit a write signal to a magnetic head having a spin torque oscillator at the time of recording data. The controller is configured to supply a drive signal that has a level higher than the ordinary level for a prescribed effective time, to the spin-torque oscillator in response to an input write gate that instructs the recording of data. During a period other than prescribed effective time, the controller supplies a drive signal having the ordinary level to the spin-torque oscillator.
    Type: Grant
    Filed: July 26, 2010
    Date of Patent: September 27, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toru Ezawa, Shuichi Kojima, Masahide Kanegae, Kenichiro Yamada, Katsuhiko Koui, Masayuki Takagishi
  • Publication number: 20110228423
    Abstract: A magnetic recording head includes a first ferromagnetic layer, an intermediate layer, a third ferromagnetic layer, a first magnetic pole and a second magnetic pole. The intermediate layer is provided between the first ferromagnetic layer and the second ferromagnetic layer. The third ferromagnetic layer includes a CoIr alloy and is provided so that the first ferromagnetic layer is sandwiched between the third ferromagnetic layer and the intermediate layer. The first magnetic pole is provided so that the third ferromagnetic layer is sandwiched between the first magnetic pole and the first ferromagnetic layer. The second magnetic pole is provided so that the second ferromagnetic layer is sandwiched between the second magnetic pole and the intermediate layer.
    Type: Application
    Filed: September 13, 2010
    Publication date: September 22, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuhiko Koui, Kenichiro Yamada, Mariko Kitazaki, Hitoshi Iwasaki, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Soichi Oikawa
  • Publication number: 20110205655
    Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole, a shield, and a stacked structure body. The shield is provided to oppose the main magnetic pole. The stacked structure body is provided between the main magnetic pole and the shield. The stacked structure body includes a first magnetic layer, a second magnetic layer, and an intermediate layer. The first magnetic layer has coercivity lower than a magnetic field applied from the main magnetic pole. A size of a film surface of the second magnetic layer is larger than a size of a film surface of the first magnetic layer. The intermediate layer is provided between the first magnetic layer and the second magnetic layer and is made of a nonmagnetic material. A current is configured to pass between the first magnetic layer and the second magnetic layer.
    Type: Application
    Filed: February 7, 2011
    Publication date: August 25, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Mariko Shimizu, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Soichi Oikawa
  • Publication number: 20110205667
    Abstract: A magnetic recording head includes a magnetic pole, a spin torque oscillator, a first shield and a second shield. The magnetic pole has an air-bearing surface. The spin torque oscillator is provided so that a first side of the spin torque oscillator faces the magnetic pole in a first direction parallel to the air-bearing surface. The first shield includes a granular magnetic material, and is provided so that two portions of the first shield sandwich the spin torque oscillator in a second direction which is parallel to the air-bearing surface and perpendicular to the first direction. The second shield is provided on a second side of the spin torque oscillator opposite to the first side.
    Type: Application
    Filed: August 10, 2010
    Publication date: August 25, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro YAMADA, Katsuhiko KOUI, Mariko KITAZAKI, Masayuki TAKAGISHI, Tomomi FUNAYAMA, Masahiro TAKASHITA, Soichi OIKAWA, Akihiko TAKEO
  • Publication number: 20110128648
    Abstract: According to one embodiment, an apparatus for controlling a head includes a transmitting module and a controller. The transmitting module is configured to transmit a write signal to a magnetic head having a spin torque oscillator at the time of recording data. The controller is configured to supply a drive signal that has a level higher than the ordinary level for a prescribed effective time, to the spin-torque oscillator in response to an input write gate that instructs the recording of data. During a period other than prescribed effective time, the controller supplies a drive signal having the ordinary level to the spin-torque oscillator.
    Type: Application
    Filed: July 26, 2010
    Publication date: June 2, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Toru EZAWA, Shuichi KOJIMA, Masahide KANEGAE, Kenichiro YAMADA, Katsuhiko KOUI, Masayuki TAKAGISHI
  • Patent number: 7898774
    Abstract: A spin valve type magnetoresistive effect element for vertical electric conduction includes a magnetoresistive effect film in which a resistance adjustment layer made of a material containing conductive carriers not more than 1022/cm3 is inserted. Thus the resistance value of a portion in change of spin-relied conduction is raised to an adequate value, thereby to increase the resistance variable amount.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: March 1, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 7848063
    Abstract: According to one embodiment, a yoke-type magnetic head for reading out magnetic information from a medium in which information is magnetically recorded in a track direction, the head includes a magnetic pole which is provided on a plane perpendicular to a linear recording direction and has an opposing surface facing the medium, a saturation magnetic flux density Bs1, and a volume V1, a sub yoke which is formed on the plane by being connected to the magnetic pole, and has a length SYW in a direction perpendicular to the linear recording direction longer than a length SYH in a direction perpendicular to a surface of the medium, and a saturation magnetic flux density Bs2 and a volume V2, the product Bs2V2 of which is larger than the product Bs1V1, and a magnetoresistance effect film which is formed between the sub yoke and the opposing surface, and abuts the magnetic pole.
    Type: Grant
    Filed: June 22, 2007
    Date of Patent: December 7, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Katsuhiko Koui
  • Patent number: 7791843
    Abstract: There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, a resistance regulating layer is provided in at least one of a pinned layer, a free layer and an non-magnetic intermediate layer. The resistance regulating layer contains, as a principal component, an oxide, a nitride, a fluoride, a carbide or a boride. The resistance regulating layer may be a continuous film or may have pin holes. Thus, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.
    Type: Grant
    Filed: July 6, 2009
    Date of Patent: September 7, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
  • Patent number: 7738220
    Abstract: A magnetoresistance effect element, comprising a nonmagnetic spacer layer, first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the magnetization of the first ferromagnetic layer freely rotating in a magnetic field signal, a magnetoresistance effect-improving layer comprising a plurality of metal films and disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the magnetoresistance effect-improving layer, one of the plurality of metal films disposed in contact with the first ferromagnetic layer contains metal element of not solid solution with metal element of the first ferromagnetic layer and a nonmagnetic underlayer or a nonmagnetic protecting layer disposed in contact with the magnetoresistance effect-improving la
    Type: Grant
    Filed: July 17, 2007
    Date of Patent: June 15, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
  • Publication number: 20100142088
    Abstract: A spin torque oscillator includes an amorphous soft magnetic layer, a nonmagnetic layer and a hard magnetic layer. The nonmagnetic layer with a close-packed crystal structure is provided on the amorphous soft magnetic layer. The hard magnetic layer with a close-packed crystal structure and perpendicular magnetic anisotropy is provided on the nonmagnetic layer.
    Type: Application
    Filed: October 6, 2009
    Publication date: June 10, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hitoshi Iwasaki, Soichi Oikawa, Katsuhiko Koui, Kenichiro Yamada
  • Publication number: 20100110592
    Abstract: A spin torque oscillator includes a first magnetic layer, a second magnetic layer and a first nonmagnetic layer. The first magnetic layer includes a magnetic film of a magnetic material with a body-centered cubic (bcc) structure and an oriented {110} plane of the body-centered cubic structure, the oriented {110} plane being oriented substantially parallel to a principal plane of the magnetic film. The first nonmagnetic layer is disposed between the first magnetic layer and the second magnetic layer. In addition, a magnetic moment in the magnetic film precesses around an axis substantially parallel to the principal plane. Furthermore, a magnetic field is applied in a direction substantially perpendicular to the principal plane, and a current is passed perpendicularly to the principal plane.
    Type: Application
    Filed: November 5, 2009
    Publication date: May 6, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuhiko Koui, Mariko Shimizu, Kenichiro Yamada